Proton therapy is an advanced radiation treatment using a proton beam to destroy diseased cells while effectively sparing surrounding healthy tissue. The chief advantage of proton therapy over other conventional radiotherapies, such as X-ray or neutron radiation therapy, is the ability to administer treatment dosages three-dimensionally by specifying the depth of radiation due to low proton beam penetration. The proton beam can be focused directly on a target volume (e.g., cancerous tissues) and the inadvertent harm to the surrounding healthy tissues can be effectively restricted. This enables a proton therapy treatment to localize the radiation dosage more precisely than other types of external beam radiotherapy.
During the operation of a typical proton beam irradiation system, a particle accelerator, such as a cyclotron, is used to generate a beam of protons for example from an internal ion source. The protons in the beam are accelerated and guided through a beam-line by a combination of magnetic fields and electric fields. Eventually, a proton beam is output through a scanning nozzle to irradiate a target volume or area of a patient's body. Particularly, in proton pencil beam scanning, a planning target volume (PVT) of a treatment site is irradiated as a series of layers and proton irradiation is delivered one layer at a time.
A proton radiation treatment system usually is connected to a computing device so that a therapist conducting a treatment session can interact with the treatment system. Through a computer implemented user interface, for example, the computing device can receive the therapist's instructions to control the treatment system operations as well as present the operational statuses of various components in the treatment system.
In general, it is desirable that the anatomy of an irradiation target volume can be visually presented to the therapist before, during and after an irradiation therapy session for purposes of preview, verification, monitoring, and assessment of the therapy process. Such visualization capabilities are common to X-ray radiation treatment systems. For example, a beam's eye view with a view angle oriented along the desired beam angle can be generated by exposing a high energy film or an electronic portal imaging device (EPID) with the treatment X-ray itself after it passes through the patient's body and any beam modifiers, e.g., an amplifier.
However, in proton as well as other charged particle radiation therapies, there is a lack of particles passing through a patient's body and so the information to produce a dynamic anatomical visualization is not readily available. As a consequence, a proton radiation therapist is incapable of conveniently visualizing a treatment site per treatment plan prior to the treatment, and incapable of monitoring the irradiation progress during the treatment, or visualizing and evaluating the results of irradiation after the treatment.